Re: Cool Frame Ideas?
 

Would you mind sharing from where you're getting the nylon connectors? I've been investigating using something like those recently and haven't found very many sources for them. I'm trying to get an idea for what's available, at what cost, and what the lead times are like for getting them delivered.

Thanks if you can help :)

Re: Cool Frame Ideas?
 

Your local 80/20 distributor should have them. The tube is $0.13 an inch (it is a special square extrusion with ridges on the inside of the tube, which I assume increase the strength of the connection) and the connector price varies depending on which one you get (straight through, t connection, 6-way, etc), but they all are between $2 and $3 each. My copy of the 80/20 price list is from last March so prices may have changed a tad, but these numbers should be pretty close.

Re: Cool Frame Ideas?
 

I disagree. We use the 1 1/2" Aluminum tubing and it makes it much stronger. Last year, our robot got tipped over 3 times and did not show the slightest hint of damage. When making a frame, keep in mind that the best robot is lousy once it falls apart. The main point of the frame is to keep everything from falling apart. It does not necessarily have to be fancy, it just has to be functional. Remember, function over form.

Re: Cool Frame Ideas?
 

I didn't even think that it would be produced by the same folks that market the T-slot extrusion. Thanks.

Has anyone used these connectors with more conventional 1x1x.0625" tubing? I'd rather not need special tubing when I've got a local supplier for metal stock and a few dozen feet sitting in the workshop already.

Re: Cool Frame Ideas?
 

Obviously 1 1/2" tubing is stronger than 3/4" tubing. It is also heavier and takes up more space. We have had no damage to our welded 3/4" thin-wall tubing superstructures for the past two years (despite "vigorous" interaction with other machines), but we do design our superstructures for using the finer tubing, with some good gusseting at the corners.

There is nothing wrong with making your robot stronger and stiffer, for as you say a broken robot is no fun. Teams need to make a trade off between strength and weight that only they can decide. We have found success building very durable, lightweight superstructures (which we weld to the KOP frame) with 3/4" square thin-wall Al tubing.

Jason

Re: Cool Frame Ideas?
 

You might want to check with someone on 1089 I know they use the connectors, but I think they are using standard aluminum. I will caution you though, the 80/20 tubing is ribbed on the inside to grip the nylon connectors better. Also I've been using http://stores.ebay.com/8020-Inc-Gara...Q3amesstQQtZkm

this store on Ebay. They have a pretty decent turn around time most parts ship in a day or two and you can generally find parts cheaper through them.

Re: Cool Frame Ideas?
 

I didn't say a thing about using it in the drivebase. Superstructure is the part of the robot above the drviebase. On our robot, we use 1 1/2" x 1" x 3/4" tubing for the drive frame and key superstructre (masts for arms, for example). 3/4" thinwall is used for stuff where we either need it to weigh nothing or we don't really care. It is pretty strong though. 330 used it for ramp framing last year. It supported about 140 lbs, often charging onto it, and we were more worried about the corrugated plastic being gouged than we were about the frame. I just wouldn't recommend using it for a drivebase.

Re: Cool Frame Ideas?
 

Here's a product I found...I haven't invested any funds to buy pieces for testing, but it looks great for making quick prototype frames:

http://www.eztube.com/

Re: Cool Frame Ideas?
 

If a team had the money and time...

I'd love to see a demo robot built with polished brass or copper tubing.
Or one with some nice stained polished hard wood. :D

I know it would never work in competition hence the demo but it would look awesome and be a cool way to show off robotics in general.
Maybe in a off season there could be a American Robot build off :cool:

Re: Cool Frame Ideas?
 

Watch out! :ahh:

We tried this stuff and it does look fantastic on paper, but they have a huge issue with being out of square. Well, not the connectors themselves, but what you put together with them. When we tapped our connectors in everything was nice and strong... but horribly out of square.

The robot frame we put together couldn't even hold an axle straight, let alone sit level. Maybe if you used force gauges or something when pressing the connectors in, or had really close tolerancs on the ID of the tube you use it would work... but just a heads up, with your ajax square tube it doesn't look too pretty... :(

-q

Re: Cool Frame Ideas?
 

The EZ Tube was exactally what I was looking for someone to say. Did you use your own extrusions or the Eztube extrusions made for the connetors, did you use the composite or the steel core?

Re: Cool Frame Ideas?
 

Last year with 1493 we built a custom frame, the sides contained the transmission (a custom 2 speed based off the AndyMark shifter) and the wheels, the two sides were connected by 1 inch square tubing with 1 inch solid aluminum cubes welded on the ends. We threaded the cubes and connected the sides with counter sunk bolts. this allowed us to quickly remove one entire drive module and replace it with a spare. Allowing us to make repairs without having to miss matches of work directly around the robot.

I am going to attach a picture of the chassis, if you have any questions feel free to ask.

Re: Cool Frame Ideas?
 

Maybe with gusseting, it would be fine. And I will admit some of the older teams make some great bases with the 3/4" tubing. However, to all of the new teams out there, you probably do not want to try this on your first bot. It works but you need to be well versed with stress analysis. Also, I suggest you have plenty of welders as I believe that you will have many more joints to cover. If, after reading this, you new teams are still confident on using this for your frame, Good Luck.

Re: Cool Frame Ideas?
 

Madison et al.

We have used 80/20 QuickFrame extensively for the last two years. We haven't used it for the chassis but for most all of the other structural components. It is really great stuff and easy to work with. All you need is a miter saw and a rubber mallet. If you want to take it apart heat the aluminum near the connector with a propane torch to expand the aluminun just a little and then the connector will usually slide right out to be reused. The only downside is the plastic connectors aren't exactly light and can start to add up if you are trying to squeze out that extra pound or two of weight budget. We bought a bunch of stock and connectors in 2006 and will probably need to restock some this year. I don't know where everyone else buys their 80/20 material but we went through our regional distributor and they gave us quite a nice educational discount. IIRC it was something like 40% and I was under the impression this was the standard 80/20 discount for all FIRST teams.

As far as using the connectors with standard 1" thin walled square tubing I really don't think it will work. The 1" square 80/20 QuickFrame tubing is specially fitted for the connectors. It has longitudinal ribbing inside that forms a friction lock with the plastic connectors. This is sort of the secret to the whole system. The internal dimensions of the QuickFrame tubing is slightly smaller (thicker walled than standard 1" thin wall box tubing) so if you try to insert a QuickFrame connector into standard 1" thin walled box tubing the connector will just fall out (too loose). The tubing isn't really that expensive though. IIRC the standard 1" QuickFrame box tubing was about $10-$11 per 12 foot (145") piece after the discount. They also have tubing with flanges on the side in different arrangements for putting panels in, etc. We purchased some but didn't really use the flanges much and often just cut them off to save weight.

One trick we found was to drill a hole in the end of the tube through into the connector and put a pop rivet in on any connectors you REALLY don't want to back out. This trick is rarely needed but is cheap (and light) insurance.

There are also 80/20 "transition" connectors available to use QuickFrame in combination with 1010 series where needed.

Search CD media photos for our team number "456" and there are 4 photos, 2 of our 06 and 2 of our 07 (1 lifting our 06) robot showing lots of use of 80/20 QuickFrame.

Oh yeah, we have used the KitBot frame for the last two years but the QuickFrame matches perfectly to the 1/4" 1" spaced hole pattern of the KitBot frame if you use the little base connector (part number 9140(gray) or 9240 (black)).

Hope this helps. Any more questions just ask.

Edit: I forgot the mention that 80/20 QuickFrame isn't really made by 80/20 but rather by Esto.

Re: Cool Frame Ideas?
 

We have used welded 1" aluminum for our frame 3 out of the last four years with great success. The other year we used the kit box frame welded together.

We have also used 1" thin wall for the superstructure but connected together with gussets and rivets. No need for fancy connectors or welding. Only tools needed are a hacksaw, tin snips, a drill and pop rivet gun.